To clarify: This is about a avatar image on Gerrit for the Tricium service account, e.g. when it adds comments, right? And the commit queue logo is the one used by https://chromium-review.googlesource.com/dashboard/commit-bot@chromium.org?

Yes, correct. Sorry for being unclear, I should've added some pointers.

I wonder how to change account details on Gerrit for service accounts... would tricium-dev@appspot.gserviceaccount.com and tricium-prod@appspot.gserviceaccount.com have passwords for Gerrit?

The commit queue has a real chromium address commit-bot@chromium.org, as this predates IAM. This is not the case for real service accounts. But since it's really just an OAuth2 identity, maybe it's possible if we find the datasource gerrit is using.

Based on https://bugs.chromium.org/p/chromium/issues/detail?id=772391#c24, it sounds like it might not be possible to set avatar images for service accounts.

Relevant code in Gerrit:
https://cs.corp.google.com/piper///depot/google3/java/com/google/devtools/gerritcodereview/server/auth/GoogleAvatar.java?rcl=176395316&l=71

Closing based on #5.